In a recent interview at the Pixar headquarters in Emeryville, Calif. to promote the upcoming "Monsters University," Crystal told a group of reporters what cool customers his four grandchildren are. They didn't know that their grandpa had any kind of special status until a paparazzo was following the actor and kids around The Grove, an upscale outdoor mall in L.A., taking pictures, prompting the kids to ask what the fuss was about.

Their nonplussed attitude toward Crystal shouldn't be a total surprise, of course; as the actor said, it's not like his biggest live-action movies are suitable for younger audiences. "I couldn't show them 'When Harry Met Sally,'" he said, before imagining a conversation with the youngsters. "'Why is she going, 'Yes, yes, yes'?' 'You'll find out.'"

Thank goodness then for his 2001 film "Monsters, Inc." "Then I was Grandpa Mike Wazowski."

"I'd answer the phone, when they'd call, 'Hi,' 'Oh, is Grandpa Mike Wazowski there?' 'Hold on, I'll get him... Mike! The kids wanna talk to you.'" He put on the New York accent he uses for the character in "Monsters Inc." and "Monsters University." "'Again? All right, hi, hi.' Oh boy."

At the Pixar Studio store, later, Crystal shopped with an assistant, asking if they had "anything pink" with his character on it. (His two eldest grandchildren are girls aged 10 and 7; that paparazzo mentioned earlier was stalking the group at the American Girl doll store. "I wish he'd followed me to the cash register," Crystal joked.)

Pixar

His grandkids will surely get a kick out of "Monsters University" as well when it opens June 21. The prequel follows monsters Mike Wazowski and James "Sully" Sullivan (voiced by John Goodman) as students at that hallowed hall of higher monster learning, Monsters University. The two begin as enemies and rival scare students both determined to get a coveted post-grad spot on the scare floor we already know from "Monsters Inc." (Spoiler alert: They get there, but not in the way you'd expect.) Though far from a child, Crystal himself also enjoyed the movie, a full cut of which he recently saw.

"I saw little pieces along the way, but really little pieces, and I saw it last month and met the cast. I mean, you don't work with anybody! I didn't know that some of the people were in the movie." One good friend's vocal presence was a particular surprise. "I didn't even know Helen [Mirren] was in the movie!"

"But I think just for me, just satisfaction-wise, this is more than I expected," he said. "I was just taken away with it."

As for his real life, Crystal said that he has several friends from high school who are the Sully to his Mike.

“Your first friends are your truest friends, I find. And the ones that stick are really special. They're my first call, and we're coming up to our — oh, s**t — our 50th high school reunion in 2015, so they've already started planning something.”